Ellipse scriber



Dec. 21, 1965 TERRELL 3,224,098

ELLIPSE SCRIBER Filed Sept. 8, 1964 2 Sheets-Sheet '1 IO) LIJ 3 ll JOSEPH D. TERRELL l N VE NTC I2 ATTOR NEYS J. D. TERRELL.

ELLIPSE SCRIBER Dec. 21, 1965 2 Sheets-Sheet 2 Filed Sept. 8, 1964 J'osEPH D. TEREELL INVENTOIZ ZeMZaan ATTOR EY S 3,224,098 ELLIISE SQRIBER Joseph D. Terreil, 1634 Shatto t., Los Angeles, Calif. Filed Sept. 8, 1964, Ser. No. 394,946 1 Qlairn. (Cl. 33-31)) The invention relates to an instrument of the kind useful to mechanics such as sign painters, cabinet makers, glass cutters, etc., by means of which the mechanic is able to lay out an arc of elliptical pattern which is true and accurate to the extent that accuracy is necessary for Work of that general nature. More particularly, the invention relates to what currently is referred to as a kit adapted to be mounted upon a conventional yardstick which then becomes part of the device for scribing an ellipse.

Unlike the scribing of a circle which has but one radius an ellipse presents an appreciably greater problem because inasmuch as it has two different radii, a change in one or the other produces an elliptical pattern which is correspondingly different. The elliptical pattern may vary considerably from a long narrow pattern to one which is so short and rounded as to closely approximate a circular pattern. There are, of course, an infinite number of variations between the two. Various instruments have been devised for the striking of a perfect elliptical outline when the major and minor axes are known. Except for the fact that the instruments of the kind made reference to are capable of being set to scribe a perfect ellipse, they are not always helpful to a workman like a sign painter, a glass cutter, or a cabinet maker, to mention a few, who does not need exact precision but who needs instead a quick, handy and effective instrument which can be employed wherever workmen chance to be. Such an instrument also must be one which Will not be easily knocked out of adjustment such as could easily happen should the workman attempt to make use of the delicate precise ellipse scribers heretofore available for draftsmen and engineers.

It is therefore one of the objects of the invention to provide a new and improved ellipse scriber which is readily available and sufiiciently accurate so as to be capable of readily tracing an ellipse of desirable length and breadth under whatever circumstances might be encountered in field Work.

Another object of the invention is to provide a new and improved ellipse scriber which makes possible scribing of an ellipse on virtually any relatively fiat surface, and without the use of any auxiliary guide for support.

Another object of the invention is to provide a new and improved tool capable of defining an ellipse of selected length and breadth with which virtually any type of scriber or cutter may be employed.

Another object of the invention is to provide a new and improved ellipse scriber which can be quickly and easily set to trace an ellipse of virtually any desired proportion and which for effective setting presents no need for mathematical calculation.

Still another object of the invention is to provide a new and improved ellipse scriber wherein, after a proper setting has been made, presents a relative minimum of moving and operating parts thereby to provide ample clear space when tracing the desired ellipse on an appropriate surface.

Still another object of the invention is to provide new and improved ellipse scriber which can be made up as a complete instrument or which can be supplied as a kit for application to a conventional yardstick wherein the parts are relatively simple, and inexpensive, and of such nature that they can be easily assembled and later removed with equal ease so as to be readily packed for being carried about in the workmens kit of tools.

3,224,998 Fatented Dec. 21, 1965 With these and other objects in view, the invention consists in the construction, arrangement, and combination of the various parts of the device, whereby the objects contemplated are attained, as hereinafter set forth, pointed out in the appended claim and illustrated in the accompanying drawings.

FIGURE 1 is a side perspective view showing the ellipse scriber adjusted and mounted in position occupied during the scribing of an ellipse on an appropriate surface.

FIGURE 2 is a diagrammatic view showing the outline of the ellipse scribed by the device of FIGURE 1.

FIGURE 3 is a side elevational view of the device in the initial setting phase wherein the major axis of the ellipse is being determined.

FIGURE 4 is a view similar to FIGURE 3 but where the minor axis has been determined.

FIGURE 5 is a side elevational view partially broken away including the showing of means for taking up on the cord.

FIGURE 6 is a bottom view of the device of FIG- URE 5.

FIGURE 7 is a cross sectional view taken along the line 7-7 of FIGURE 5.

FIGURE 8 is a fragmentary end perspective view showing the manner in which the cord is attached.

FIGURE 9 is a conversion chart for the device.

In an embodiment of the invention chosen for the purpose of illustration the device is shown mounted upon and combined with a substantially conventional yardstick 10, the yardstick being provided with the usual scale 11 measured ofl? in feet, inches and fractions of an inch. Two fixtures are identified respectively by the reference characters 12 and 13. The fixture 12 may be described as a block provided with an opening 14 matching in cross sectional shape and size the cross sectional shape and size of the yardstick 10. A thumb screw 15 threadedly engages the block and can be tightened into engagement with a side face of the yardstick 10 to securely anchor the fixture 12 upon the end of the yardstick.

A positioning stud 16 extends from one end of the block at the outer end of which is a pivot point 17 which is intended to substantially coincide with an index zero 18 of the yardstick.

The fixture 13 may be described as a sliding head or carriage having a 'bore 20 extending through it from one end 22 to an opposite end 23, the bore having substantially the same cross sectional shape and size as the cross sectional shape and size of the yardstick 10 so as to slidably accommodate the yardstick. A tightener in the form of thumb screw 24 has a threaded engagement in a plate 25 and extends through the side of the fixture into engagement with the yardstick 10 thereby to releasably fix the position of the fixture upon the yardstick.

At the end 22 of the fixture 13 is a positioning post 26 which extends from the fixture in a direction parallel to the stud 16. At the outer end of the post 26 is a rectangular loop 27 at the outer end of which is a pivot 28 similar to the pivot 17. The pivots 17 and 28 are preferably parallel to each other and terminate in the same plane so that when resting upon a surface 30 for example, on which work is to be done the yardstick will be in a substantially parallel position with respect to the surface.

To a fastener in the form of a button 31 on the end 22 of the fixture 13 is anchored an end 32 of a cord 33. The cord passes through the rectangular loop 27 in a reverse direction as pictured in FIGURE 8 and then makes an endless bight indicated generally by the reference character 34, returning to the rear side of the rectangular loop 27 through which it passes. The cord then makes one or two turns around another fastener in the form of a tension disc 35 which is fastened at one side of the post 26. The cord then passes for convenience through a bracket 36 to a storage reel 37 which is manipulated by a crank arm 38 and handle 39. A space 40 is provided intermediate opposite sides of the fixture 13 into which the cord passes to its point of engagement with the reel 37. By this arrangement slack in the cord 33 can be taken up and any surplus amount of cord is retained concealed and out of the Way within the space 46.

A guide spool 42 is provided on one side with an eyelet 43 through which the cord passes. The guide spool has at least one flat face 44 which is adapted to ride over the surface 30 and is provided with an opening 45 for reception of a stylus like the stylus 46 which may be a pencil, a marking scriber, a knife, or other appropriate scribing medium.

In operation when there is need to circumscribe an ellipse like the ellipse 50 shown in FIGURE 2 the long axis X and the short axis Y are determined. Let it be assumed for the purpose of illustration that the long or major axis is 8 inches and that the short or minor axis is inches. On a chart like that shown in FIGURE 9 the initial setting of the fixture 13 is indicated as 6% inches. Loosening the thumb screw 24 to permit the fixture 13 to slide along the yardstick the fixture is slid until the end 22 coincides with the 6% inch mark on the yardstick as indicated in FIGURE 3. The thumb screw is then tightened to hold the fixture 13 temporarily in the selected position. The guide spool 42 is placed over the stud 16 and the cord is drawn tight and wound around the tension disc 35 to hold it securely in the selected position of FIGURE 3. Any surplus length of cord is drawn up out of the way as previously described by the reel 37. The thumb screw 24 is then loosened and the fixture 13 reset at a position such that the end 22 coincides with the 5% inch calibration on the scale 10 since this is the calibration found on the chart corresponding to the short or minor axis Y of the ellipse which is to be circumscribed. The device is now ready for operation.

Both pivots 17 and 28 are now firmly pressed upon the surface 30 at the locations selected depending upon where the ellipse 50 is to be drawn. The stylus 46 is then inserted into the opening 45 of the guide spool 42 and the stylus is then preferably started at a point 51 which is rearward and to the right. The stylus is then swung forwardly and toward the right as permitted by the length of the cord thereby first to trace a portion 52 of the ellipse 50. The tracing then carries on forwardly of the. fixture 12 then around outwardly and rearwardly toward the left tracing a portion 53 of the ellipse, as shown effectively in FIGURE 1. Thereafter the stylus continues to be swung inwardly and rearwardly so that it will ultimately trace the broken line portion 54 of the ellipse 50 until it finally closes adjacent the starting point 51. The ellipse is then complete. The procedure can be repeated if another ellipse of identical shape, size and proportion is desired. If however an ellipse of different size, shape and proportion is to -be drawn, the fixture 13 will then be reset to a corresponding location on the scale It) as was described initially and, after the cord 33 has been appropriately tightened the fixture 13 is reset to the new location determined again by reference to the chart or table of FIGURE 9 and the instrument is then ready for scribing the newly proportioned ellipse.

When the device is no longer needed the thumb screw is loosened as is also the thumb screw 24, the fixtures 12 and 13 removed from the yardstick'and the fixtures with the accompanying cord can then be readily packed by the operator in his kit until there is again need for the device.

It will be appreciated that the need for the chart for table of FIGURE 9 is to compensate for empirical distances in the equipment which depends in part upon the material used and the accuracy of construction of the fixtures and the locations of the pivots on the fixtures. Again having in mind that the device of the invention is a practical workmans tool adapted primarily to quick and ready use under adverse circumstances in the field and that the parts like the fixtures may be subjected to some abuse when carried about, it is more essential that the fixtures and attendant parts may be made rugged and to substantially the accuracy desired and that an appropriate chart matched to the physical structure be printed on a side face of the fixture 13 where ready reference can be had to it in the manner described when the device is to be used. Should further variations in the proportions of a desired ellipse be desired such variations can be readily determined by extrapolation from the suggested values of the chart.

While the invention has herein been shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claim so as to embrace any and all equivalent devices.

Having described the invention, what is claimed as new in support of Letters Patent is:

An ellipse scriber device comprising a rigid shaft of rectangular cross-sectional shape, a positioning stud having a fixed position at one end of the shaft, said stud extending from one edge of the shaft and terminating in a point extending longitudinally endward at the free end of said stud, a graduation ion a fiat side of said shaft, a carriage having a shoulder in positioning relationship with said graduation, said carriage having a rectangular bore therethrough slidably mounting said carriage on said shaft. and a tightener acting between said carriage and said shaft to fasten the carriage at selected positions on said shaft, a positioning post on said carriage substantially parallel to said stud and to said shaft, said positioning post terminating in a point extending longitudinally endward at the free end thereof, said last point being at the same distance from said one edge of the shaft as the point on said stud, first and second fasteners on said post adjacent the point thereon and a storage reel rotatably mounted on said carriage on an axis perpendicular to said flat side of the shaft, said reel being on the same side of said shaft as said positioning post and substantially in the same plane as said stud and said post, a cord having one end fixed to the first of said fasteners on the post and the other end extending around said storage reel, said post having a passage therethrough for the cord, said cord being adapted to extend from said first of said fasteners around said positioning stud, then through the passage in said post to releasable engagement with the second of said fasteners and thence to said storage reel, and guide means for a scriber in slidalJle engagement with said cord from a position at one end thereof adjacent said positioning post to a position adjacent said positioning post at the other end of the cord.

References Cited by the Examiner UNITED STATES PATENTS 1,022,969 4/1912 Ohye 33-30 1,488,641 4/1924 Johnston 3330 1,724,738 8/1929 Stossel 33-30 1,921,892 8/1933 Sommer 3330 FOREIGN PATENTS 191,645 1/ 1923 Great Britain. 422,127 6/ 1947 Italy.

ISAAC LISANN, Primary Examiner. 

